The present invention is generally related to battery chargers and more particularly to an improved battery charger for rapidly and safely charging batteries in radio transceivers.
In the prior art, battery chargers have typically provided a relatively high charging current to a battery until the battery voltage reaches a predetermined voltage. Rapidly charging a battery, in particular nickel-cadmium batteries, may produce gas and high temperatures causing the battery to dry out and rupture or possibly explode. Therefore, chargers such as that shown and described in U.S. Pat. No. 3,767,995 (incorporated herein in its entirety by reference thereto) may also sense the temperature of a battery being charged and reduce the charging rate when the battery temperature rises above a predetermined temperature. However, such prior art battery chargers may still cause a battery to rupture or possibly explode if the battery is subjected to a charging current midway between the high-rate and low-rate charging currents due to low voltage or low current from the power supply.